import {
  FORBIDDEN_COLOR_RE,
  INTERACTIVE_DEMO_CAPS,
  isHumanStringKey,
} from './constants'
import { interactiveDemoV1Schema } from './schema'
import type {
  DemoAct,
  DemoScene,
  InteractiveDemoV1,
  Panel,
  ValidationIssue,
  ValidationResult,
} from './types'

function issue(code: string, path: string, message: string): ValidationIssue {
  return { code, path, message }
}

function escapeRegExp(s: string): string {
  return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
}

/** Heatmap cell ids — respect triangular mode (lower → 36 cells for 8×8). */
export function heatmapCellIds(
  rows: number,
  cols: number,
  triangular?: 'lower' | 'upper' | 'none'
): string[] {
  const ids: string[] = []
  for (let r = 1; r <= rows; r++) {
    for (let c = 1; c <= cols; c++) {
      if (triangular === 'lower' && c > r) continue
      if (triangular === 'upper' && c < r) continue
      ids.push(`r${r}.c${c}`)
    }
  }
  return ids
}

/** Collect every addressable element id in a scene (nodes, edges, series, heatmap cells). */
export function collectSceneElementIds(scene: DemoScene): {
  ids: Set<string>
  wildcardAllowed: boolean
} {
  const ids = new Set<string>()
  let wildcardAllowed = false

  for (const panel of scene.panels) {
    if (panel.type === 'svg-scene') {
      for (const n of panel.payload.nodes) ids.add(n.id)
      for (const e of panel.payload.edges ?? []) {
        ids.add(e.id)
      }
    } else if (panel.type === 'chart') {
      wildcardAllowed = true
      for (const s of panel.payload.series) ids.add(s.id)
    } else if (panel.type === 'heatmap-matrix') {
      wildcardAllowed = true
      const { rows, cols, triangular } = panel.payload
      for (const id of heatmapCellIds(rows, cols, triangular)) {
        ids.add(id)
      }
    }
  }

  return { ids, wildcardAllowed }
}

function countDeclaredScenes(demo: InteractiveDemoV1): number {
  let n = 1 // demo.scene
  for (const act of demo.acts) {
    if (act.scene) n += 1
  }
  return n
}

/**
 * Scan for free color literals — skip human/translatable string fields
 * so prose like « couleur #FF0000 » does not hard-reject.
 */
function scanForbiddenColors(
  value: unknown,
  path: string,
  out: ValidationIssue[]
): void {
  if (typeof value === 'string') {
    if (FORBIDDEN_COLOR_RE.test(value)) {
      out.push(
        issue(
          'forbidden_color',
          path,
          'Free color literals (hex/rgb) are forbidden — use intent enums'
        )
      )
    }
    return
  }
  if (Array.isArray(value)) {
    value.forEach((v, i) => scanForbiddenColors(v, `${path}[${i}]`, out))
    return
  }
  if (value && typeof value === 'object') {
    for (const [k, v] of Object.entries(value)) {
      if (isHumanStringKey(k)) continue
      scanForbiddenColors(v, path ? `${path}.${k}` : k, out)
    }
  }
}

function validateSvgEdges(panel: Panel, path: string, out: ValidationIssue[]): void {
  if (panel.type !== 'svg-scene') return
  const nodeIds = new Set(panel.payload.nodes.map((n) => n.id))
  for (const [i, edge] of (panel.payload.edges ?? []).entries()) {
    if (!nodeIds.has(edge.from)) {
      out.push(
        issue(
          'unknown_edge_endpoint',
          `${path}.edges[${i}].from`,
          `Edge from "${edge.from}" is not a node id in this panel`
        )
      )
    }
    if (!nodeIds.has(edge.to)) {
      out.push(
        issue(
          'unknown_edge_endpoint',
          `${path}.edges[${i}].to`,
          `Edge to "${edge.to}" is not a node id in this panel`
        )
      )
    }
  }
}

function validateHeatmapShape(panel: Panel, path: string, out: ValidationIssue[]): void {
  if (panel.type !== 'heatmap-matrix') return
  const { rows, cols, values, rowLabels, colLabels } = panel.payload
  if (values.length !== rows) {
    out.push(
      issue(
        'heatmap_shape',
        `${path}.values`,
        `Expected ${rows} rows, got ${values.length}`
      )
    )
  }
  for (const [ri, row] of values.entries()) {
    if (row.length !== cols) {
      out.push(
        issue(
          'heatmap_shape',
          `${path}.values[${ri}]`,
          `Expected ${cols} cols, got ${row.length}`
        )
      )
    }
  }
  if (rowLabels && rowLabels.length !== rows) {
    out.push(
      issue(
        'heatmap_labels',
        `${path}.rowLabels`,
        `rowLabels length must equal rows (${rows})`
      )
    )
  }
  if (colLabels && colLabels.length !== cols) {
    out.push(
      issue(
        'heatmap_labels',
        `${path}.colLabels`,
        `colLabels length must equal cols (${cols})`
      )
    )
  }
}

function validateScene(
  scene: DemoScene,
  path: string,
  out: ValidationIssue[]
): Set<string> {
  const panelIds = new Set<string>()
  for (const [pi, panel] of scene.panels.entries()) {
    const pPath = `${path}.panels[${pi}]`
    if (panelIds.has(panel.id)) {
      out.push(issue('duplicate_panel_id', `${pPath}.id`, `Duplicate panel id "${panel.id}"`))
    }
    panelIds.add(panel.id)
    validateSvgEdges(panel, pPath, out)
    validateHeatmapShape(panel, pPath, out)
  }

  const seen = new Set<string>()
  const dups = new Set<string>()
  for (const panel of scene.panels) {
    const local: string[] = []
    if (panel.type === 'svg-scene') {
      local.push(...panel.payload.nodes.map((n) => n.id))
      local.push(...(panel.payload.edges ?? []).map((e) => e.id))
    } else if (panel.type === 'chart') {
      local.push(...panel.payload.series.map((s) => s.id))
    }
    for (const id of local) {
      if (seen.has(id)) dups.add(id)
      seen.add(id)
    }
  }
  for (const id of dups) {
    out.push(
      issue('duplicate_element_id', path, `Duplicate element id "${id}" in scene`)
    )
  }

  return collectSceneElementIds(scene).ids
}

function validateActRefs(
  act: DemoAct,
  actIndex: number,
  elementIds: Set<string>,
  wildcardAllowed: boolean,
  out: ValidationIssue[]
): void {
  const actPath = `acts[${actIndex}]`
  const stepIdRe = new RegExp(`^${escapeRegExp(act.id)}\\.s\\d+$`)

  for (const [si, step] of act.steps.entries()) {
    const stepPath = `${actPath}.steps[${si}]`
    if (!stepIdRe.test(step.id)) {
      out.push(
        issue(
          'step_id_format',
          `${stepPath}.id`,
          `Step id must match /^${act.id}\\.s\\d+$/ (got "${step.id}")`
        )
      )
    }

    for (const id of step.pointTo ?? []) {
      if (!elementIds.has(id)) {
        out.push(
          issue(
            'unknown_element_id',
            `${stepPath}.pointTo`,
            `pointTo references unknown element "${id}" in active scene`
          )
        )
      }
    }

    for (const [ri, rev] of (step.reveal ?? []).entries()) {
      for (const id of rev.ids) {
        if (id === '*') {
          if (!wildcardAllowed) {
            out.push(
              issue(
                'wildcard_not_allowed',
                `${stepPath}.reveal[${ri}]`,
                '"*" reveal is only allowed when the active scene has heatmap or chart panels'
              )
            )
          }
          continue
        }
        if (!elementIds.has(id)) {
          out.push(
            issue(
              'unknown_element_id',
              `${stepPath}.reveal[${ri}].ids`,
              `reveal references unknown element "${id}"`
            )
          )
        }
      }
    }

    for (const [ai, ann] of (step.annotate ?? []).entries()) {
      for (const id of ann.targetIds) {
        if ((step.pointTo ?? []).includes(id)) {
          out.push(
            issue(
              'annotate_pointto_overlap',
              `${stepPath}.annotate[${ai}]`,
              `Do not annotate "${id}" in the same step as pointTo — spotlight is enough`
            )
          )
        }
        if (!elementIds.has(id)) {
          out.push(
            issue(
              'unknown_element_id',
              `${stepPath}.annotate[${ai}].targetIds`,
              `annotate references unknown element "${id}"`
            )
          )
        }
      }
    }
  }
}

function semanticValidate(demo: InteractiveDemoV1): ValidationIssue[] {
  const out: ValidationIssue[] = []

  const jsonBytes = new TextEncoder().encode(JSON.stringify(demo)).length
  if (jsonBytes > INTERACTIVE_DEMO_CAPS.maxJsonBytes) {
    out.push(
      issue(
        'json_too_large',
        '',
        `JSON exceeds ${INTERACTIVE_DEMO_CAPS.maxJsonBytes} bytes (${jsonBytes})`
      )
    )
  }

  const sceneCount = countDeclaredScenes(demo)
  if (sceneCount > INTERACTIVE_DEMO_CAPS.maxScenes) {
    out.push(
      issue(
        'too_many_scenes',
        'scene',
        `At most ${INTERACTIVE_DEMO_CAPS.maxScenes} scenes allowed (found ${sceneCount})`
      )
    )
  }

  scanForbiddenColors(demo, '', out)

  validateScene(demo.scene, 'scene', out)

  let activeScene = demo.scene
  let { ids: elementIds, wildcardAllowed } = collectSceneElementIds(activeScene)

  const actIds = new Set<string>()
  for (const [ai, act] of demo.acts.entries()) {
    if (actIds.has(act.id)) {
      out.push(issue('duplicate_act_id', `acts[${ai}].id`, `Duplicate act id "${act.id}"`))
    }
    actIds.add(act.id)

    if (act.scene) {
      validateScene(act.scene, `acts[${ai}].scene`, out)
      activeScene = act.scene
      ;({ ids: elementIds, wildcardAllowed } = collectSceneElementIds(activeScene))
    }

    const stepIds = new Set<string>()
    for (const [si, step] of act.steps.entries()) {
      if (stepIds.has(step.id)) {
        out.push(
          issue(
            'duplicate_step_id',
            `acts[${ai}].steps[${si}].id`,
            `Duplicate step id "${step.id}"`
          )
        )
      }
      stepIds.add(step.id)
    }

    validateActRefs(act, ai, elementIds, wildcardAllowed, out)
  }

  return out
}

/**
 * Validate an Interactive Demo document.
 * Structural (Zod allowlist) then semantic (caps, refs, no hex, wildcards).
 */
export function validateInteractiveDemo(input: unknown): ValidationResult {
  const parsed = interactiveDemoV1Schema.safeParse(input)
  if (!parsed.success) {
    const issues: ValidationIssue[] = parsed.error.issues.map((e) => ({
      code: e.code,
      path: e.path.join('.'),
      message: e.message,
    }))
    return { ok: false, issues }
  }

  const demo = parsed.data as InteractiveDemoV1
  const semantic = semanticValidate(demo)
  if (semantic.length > 0) {
    return { ok: false, issues: semantic }
  }
  return { ok: true, demo }
}

/**
 * Translate must preserve geometry. Default: strings are structural (kept).
 * Only HUMAN_STRING_KEYS are nullified — adding a structural key is protected by default.
 */
export function assertTranslatePreservesStructure(
  source: InteractiveDemoV1,
  translated: InteractiveDemoV1
): ValidationResult {
  const stripHumanStrings = (value: unknown): unknown => {
    if (typeof value === 'number' || typeof value === 'boolean' || value === null) {
      return value
    }
    if (typeof value === 'string') {
      // Context-free string: structural until proven otherwise.
      return value
    }
    if (Array.isArray(value)) return value.map(stripHumanStrings)
    if (value && typeof value === 'object') {
      const out: Record<string, unknown> = {}
      for (const [k, v] of Object.entries(value)) {
        if (isHumanStringKey(k)) {
          out[k] = null
          continue
        }
        out[k] = stripHumanStrings(v)
      }
      return out
    }
    return value
  }

  const a = JSON.stringify(stripHumanStrings(source))
  const b = JSON.stringify(stripHumanStrings(translated))
  if (a !== b) {
    return {
      ok: false,
      issues: [
        issue(
          'translate_structure_drift',
          '',
          'Translated demo must preserve structure and ids; only human strings may change'
        ),
      ],
    }
  }

  if (source.id !== translated.id) {
    return {
      ok: false,
      issues: [
        issue(
          'translate_id_mismatch',
          'id',
          'Translated variant must keep the same demo.id'
        ),
      ],
    }
  }

  return { ok: true, demo: translated }
}