lightspeed

//// Deterministic documentation-system conformance harness for M46.

import gleam/int
import gleam/list
import gleam/string
import lightspeed/tooling/documentation_system

pub const snapshot_version = 1

/// M46 conformance scenarios.
pub type Scenario {
  CoherentDocumentationSystemSurface
  RoadmapModuleFixtureDriftContracts
  VersionedUpgradeTroubleshootingPaths
  DocumentationEvidenceUpdateRequirements
}

/// One M46 scenario outcome.
pub type ScenarioOutcome {
  ScenarioOutcome(
    scenario: Scenario,
    passed: Bool,
    deterministic: Bool,
    signature: String,
  )
}

/// Full M46 report.
pub type Report {
  Report(
    outcomes: List(ScenarioOutcome),
    failed_scenarios: Int,
    nondeterministic_failures: Int,
  )
}

/// Run all M46 scenarios.
pub fn run_matrix() -> Report {
  let outcomes =
    [
      CoherentDocumentationSystemSurface,
      RoadmapModuleFixtureDriftContracts,
      VersionedUpgradeTroubleshootingPaths,
      DocumentationEvidenceUpdateRequirements,
    ]
    |> list.map(run_scenario)

  Report(
    outcomes: outcomes,
    failed_scenarios: count_failed(outcomes),
    nondeterministic_failures: count_nondeterministic(outcomes),
  )
}

/// Run one scenario twice and require deterministic parity.
pub fn run_scenario(scenario: Scenario) -> ScenarioOutcome {
  let #(first_passed, first_signature) = evaluate(scenario)
  let #(second_passed, second_signature) = evaluate(scenario)
  let deterministic =
    first_passed == second_passed && first_signature == second_signature
  let passed = first_passed && second_passed && deterministic

  ScenarioOutcome(
    scenario: scenario,
    passed: passed,
    deterministic: deterministic,
    signature: first_signature,
  )
}

/// Scenario label.
pub fn scenario_label(scenario: Scenario) -> String {
  case scenario {
    CoherentDocumentationSystemSurface ->
      "coherent_documentation_system_surface"
    RoadmapModuleFixtureDriftContracts ->
      "roadmap_module_fixture_drift_contracts"
    VersionedUpgradeTroubleshootingPaths ->
      "versioned_upgrade_troubleshooting_paths"
    DocumentationEvidenceUpdateRequirements ->
      "documentation_evidence_update_requirements"
  }
}

/// Stable pass/fail label.
pub fn pass_fail_label(outcome: ScenarioOutcome) -> String {
  case outcome.passed {
    True -> "pass"
    False -> "fail"
  }
}

/// Scenario signature accessor.
pub fn signature(outcome: ScenarioOutcome) -> String {
  outcome.signature
}

/// Scenario accessor.
pub fn scenario(outcome: ScenarioOutcome) -> Scenario {
  outcome.scenario
}

/// Determinism accessor.
pub fn deterministic(outcome: ScenarioOutcome) -> Bool {
  outcome.deterministic
}

/// Report outcomes accessor.
pub fn outcomes(report: Report) -> List(ScenarioOutcome) {
  report.outcomes
}

/// Failed scenario count.
pub fn failed_scenarios(report: Report) -> Int {
  report.failed_scenarios
}

/// Nondeterministic scenario count.
pub fn nondeterministic_failures(report: Report) -> Int {
  report.nondeterministic_failures
}

/// Stable report signature.
pub fn report_signature(report: Report) -> String {
  let entries =
    list.map(report.outcomes, fn(outcome) {
      scenario_label(outcome.scenario)
      <> "="
      <> pass_fail_label(outcome)
      <> ":deterministic="
      <> bool_label(outcome.deterministic)
      <> ":"
      <> outcome.signature
    })

  join_with(";", entries)
}

/// Deterministic snapshot signature for M46 fixture drift gates.
pub fn snapshot_signature() -> String {
  "m46.snapshot.v"
  <> int.to_string(snapshot_version)
  <> "|"
  <> report_signature(run_matrix())
}

/// Deterministic markdown report for M46 fixture scripts.
pub fn snapshot_report_markdown() -> String {
  let report = run_matrix()
  let failed = failed_scenarios(report)
  let nondeterministic = nondeterministic_failures(report)
  let status = case failed == 0 && nondeterministic == 0 {
    True -> "OK"
    False -> "FAIL"
  }

  "# Documentation System Fixture Report\n\n"
  <> "snapshot_version: "
  <> int.to_string(snapshot_version)
  <> "\n"
  <> "status: "
  <> status
  <> "\n"
  <> "failed_scenarios: "
  <> int.to_string(failed)
  <> "\n"
  <> "nondeterministic_failures: "
  <> int.to_string(nondeterministic)
  <> "\n\n"
  <> "snapshot_signature: "
  <> snapshot_signature()
  <> "\n\n"
  <> "report_signature: "
  <> report_signature(report)
  <> "\n"
}

fn evaluate(scenario: Scenario) -> #(Bool, String) {
  case scenario {
    CoherentDocumentationSystemSurface ->
      evaluate_coherent_documentation_system_surface()
    RoadmapModuleFixtureDriftContracts ->
      evaluate_roadmap_module_fixture_drift_contracts()
    VersionedUpgradeTroubleshootingPaths ->
      evaluate_versioned_upgrade_troubleshooting_paths()
    DocumentationEvidenceUpdateRequirements ->
      evaluate_documentation_evidence_update_requirements()
  }
}

fn evaluate_coherent_documentation_system_surface() -> #(Bool, String) {
  let bundles = documentation_system.reference_bundles()
  let passed =
    documentation_system.coherent_system() && list.length(bundles) == 7
  let entries = list.map(bundles, documentation_system.signature)

  #(passed, join_with(";", entries))
}

fn evaluate_roadmap_module_fixture_drift_contracts() -> #(Bool, String) {
  let bundles = documentation_system.reference_bundles()
  let passed = documentation_system.drift_check_contracts()
  let module_entries =
    list.map(bundles, documentation_system.module_reference_signature)
  let fixture_entries =
    list.map(bundles, documentation_system.fixture_reference_signature)

  #(
    passed,
    "modules="
      <> join_with(";", module_entries)
      <> "|fixtures="
      <> join_with(";", fixture_entries),
  )
}

fn evaluate_versioned_upgrade_troubleshooting_paths() -> #(Bool, String) {
  let upgrades = documentation_system.versioned_upgrade_paths()
  let troubleshooting = documentation_system.versioned_troubleshooting_paths()
  let expected = ["m40", "m41", "m42", "m43", "m44", "m45", "m46"]
  let milestones =
    list.map(
      documentation_system.reference_bundles(),
      documentation_system.milestone,
    )
  let passed =
    milestones == expected
    && paths_use_shared_upgrade_doc(upgrades)
    && list.length(troubleshooting) == 7
  let signatures =
    list.map(
      documentation_system.reference_bundles(),
      documentation_system.upgrade_troubleshooting_signature,
    )

  #(passed, join_with(";", signatures))
}

fn evaluate_documentation_evidence_update_requirements() -> #(Bool, String) {
  let requirements = documentation_system.evidence_requirements()
  let passed =
    contains(requirements, "ROADMAP.md")
    && contains(requirements, "MILESTONES.md")
    && contains(requirements, "CHANGELOG.md")
    && contains(requirements, "rfcs/")
    && contains(requirements, "adrs/")
    && contains(requirements, "docs/milestone_upgrade_troubleshooting.md")

  #(passed, documentation_system.evidence_requirement_signature())
}

fn paths_use_shared_upgrade_doc(upgrades: List(String)) -> Bool {
  case upgrades {
    [] -> True
    [entry, ..rest] ->
      contains_string(
        entry,
        "upgrade_doc=docs/milestone_upgrade_troubleshooting.md",
      )
      && paths_use_shared_upgrade_doc(rest)
  }
}

fn count_failed(outcomes: List(ScenarioOutcome)) -> Int {
  case outcomes {
    [] -> 0
    [outcome, ..rest] ->
      case outcome.passed {
        True -> count_failed(rest)
        False -> 1 + count_failed(rest)
      }
  }
}

fn count_nondeterministic(outcomes: List(ScenarioOutcome)) -> Int {
  case outcomes {
    [] -> 0
    [outcome, ..rest] ->
      case outcome.deterministic {
        True -> count_nondeterministic(rest)
        False -> 1 + count_nondeterministic(rest)
      }
  }
}

fn contains(values: List(String), expected: String) -> Bool {
  case values {
    [] -> False
    [value, ..rest] ->
      case value == expected {
        True -> True
        False -> contains(rest, expected)
      }
  }
}

fn contains_string(value: String, expected: String) -> Bool {
  value == expected || string.contains(value, expected)
}

fn bool_label(value: Bool) -> String {
  case value {
    True -> "true"
    False -> "false"
  }
}

fn join_with(separator: String, values: List(String)) -> String {
  case values {
    [] -> ""
    [value] -> value
    [value, ..rest] -> value <> separator <> join_with(separator, rest)
  }
}