package secutools

import (
	"fmt"
	"strings"
)

// DecideProvider inspects a frontmatter map (as decoded from YAML) and
// returns the provider string that should handle the task. Valid return
// values:
//
//   - "local"       — no delegation, dispatch on a Claude Code session (Phase 1)
//   - "claude-code" — explicit local dispatch (alias of "local")
//   - "gpu"         — delegate to secutools with preferred_ai=gpu
//   - "gemini"      — delegate to secutools with preferred_ai=gemini
//   - "claude-api"  — delegate to secutools with preferred_ai=claude-api
//   - "auto"        — delegate to secutools, let smart_triage choose
//
// Precedence:
//  1. needs_claude_code: true                  → "local"
//  2. preferred_ai in {claude-code}           → "local"
//  3. allow_delegation == false / missing     → "local"
//  4. preferred_ai in {gpu,gemini,claude-api} → that provider
//  5. preferred_ai in {"", auto}              → "auto"
//  6. unknown preferred_ai                    → "local" (fail-safe)
//
// This function is intentionally permissive on input types: YAML booleans
// may decode as bool, strings as string. It coerces common forms and
// returns "local" on malformed input rather than panicking.
func DecideProvider(fm map[string]any) string {
	if fm == nil {
		return "local"
	}

	if asBool(fm["needs_claude_code"]) {
		return "local"
	}

	pref := strings.ToLower(strings.TrimSpace(asString(fm["preferred_ai"])))
	if pref == "claude-code" || pref == "local" {
		return "local"
	}

	if !asBool(fm["allow_delegation"]) {
		return "local"
	}

	switch pref {
	case "gpu", "gemini", "claude-api":
		return pref
	case "", "auto":
		return "auto"
	default:
		// Unknown provider — fail safe to local.
		return "local"
	}
}

// asBool accepts bool, "true"/"false", "1"/"0". Defaults to false.
func asBool(v any) bool {
	switch t := v.(type) {
	case bool:
		return t
	case string:
		s := strings.ToLower(strings.TrimSpace(t))
		return s == "true" || s == "1" || s == "yes"
	case int:
		return t != 0
	default:
		return false
	}
}

// asString coerces v to a trimmed string. Returns "" for nil/unknown types.
func asString(v any) string {
	switch t := v.(type) {
	case string:
		return t
	case fmt.Stringer:
		return t.String()
	case nil:
		return ""
	default:
		return fmt.Sprintf("%v", t)
	}
}