package handlers

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"

	"git.gobha.me/xcaliber/chat-switchboard/database"
)

// AuditLog inserts an audit entry. Called from mutating handlers.
// Non-blocking: errors are logged but don't break the caller.
func AuditLog(c *gin.Context, action, resourceType, resourceID string, metadata map[string]interface{}) {
	if database.DB == nil {
		return
	}

	actorID := getUserID(c)
	if actorID == "" {
		return
	}

	ip := c.ClientIP()
	ua := c.GetHeader("User-Agent")

	metaJSON := "{}"
	if metadata != nil {
		if b, err := json.Marshal(metadata); err == nil {
			metaJSON = string(b)
		}
	}

	if database.IsSQLite() {
		_, _ = database.DB.Exec(`
			INSERT INTO audit_log (id, actor_id, action, resource_type, resource_id, metadata, ip_address, user_agent)
			VALUES (?, ?, ?, ?, ?, ?, ?, ?)
		`, uuid.New().String(), actorID, action, resourceType, resourceID, metaJSON, ip, ua)
	} else {
		_, _ = database.DB.Exec(`
			INSERT INTO audit_log (actor_id, action, resource_type, resource_id, metadata, ip_address, user_agent)
			VALUES ($1, $2, $3, $4, $5::jsonb, $6, $7)
		`, actorID, action, resourceType, resourceID, metaJSON, ip, ua)
	}
}

// AuditLogAnon inserts an audit entry without a gin context (e.g. system actions).
func AuditLogAnon(action, resourceType, resourceID string, metadata map[string]interface{}) {
	if database.DB == nil {
		return
	}
	metaJSON := "{}"
	if metadata != nil {
		if b, err := json.Marshal(metadata); err == nil {
			metaJSON = string(b)
		}
	}

	if database.IsSQLite() {
		_, _ = database.DB.Exec(`
			INSERT INTO audit_log (id, action, resource_type, resource_id, metadata)
			VALUES (?, ?, ?, ?, ?)
		`, uuid.New().String(), action, resourceType, resourceID, metaJSON)
	} else {
		_, _ = database.DB.Exec(`
			INSERT INTO audit_log (action, resource_type, resource_id, metadata)
			VALUES ($1, $2, $3, $4::jsonb)
		`, action, resourceType, resourceID, metaJSON)
	}
}

// AuditLogWithActor inserts an audit entry with an explicit actor ID (e.g. pre-auth flows).
func AuditLogWithActor(actorID string, c *gin.Context, action, resourceType, resourceID string, metadata map[string]interface{}) {
	if database.DB == nil || actorID == "" {
		return
	}
	ip := c.ClientIP()
	ua := c.GetHeader("User-Agent")
	metaJSON := "{}"
	if metadata != nil {
		if b, err := json.Marshal(metadata); err == nil {
			metaJSON = string(b)
		}
	}

	if database.IsSQLite() {
		_, _ = database.DB.Exec(`
			INSERT INTO audit_log (id, actor_id, action, resource_type, resource_id, metadata, ip_address, user_agent)
			VALUES (?, ?, ?, ?, ?, ?, ?, ?)
		`, uuid.New().String(), actorID, action, resourceType, resourceID, metaJSON, ip, ua)
	} else {
		_, _ = database.DB.Exec(`
			INSERT INTO audit_log (actor_id, action, resource_type, resource_id, metadata, ip_address, user_agent)
			VALUES ($1, $2, $3, $4, $5::jsonb, $6, $7)
		`, actorID, action, resourceType, resourceID, metaJSON, ip, ua)
	}
}

// ── Admin Audit Viewer ──────────────────────

type auditEntry struct {
	ID           string  `json:"id"`
	ActorID      *string `json:"actor_id"`
	ActorName    *string `json:"actor_name"`
	Action       string  `json:"action"`
	ResourceType string  `json:"resource_type"`
	ResourceID   *string `json:"resource_id"`
	Metadata     string  `json:"metadata"`
	IPAddress    *string `json:"ip_address"`
	CreatedAt    string  `json:"created_at"`
}

// ListAuditLog returns paginated audit entries with optional filters.
// GET /api/v1/admin/audit?page=1&per_page=50&action=user.create&actor_id=...&resource_type=...
func (h *AdminHandler) ListAuditLog(c *gin.Context) {
	page, perPage, offset := parsePagination(c)

	// Build filter clauses with ? placeholders, convert for Postgres later
	where := "WHERE 1=1"
	args := []interface{}{}

	if action := c.Query("action"); action != "" {
		where += " AND al.action = ?"
		args = append(args, action)
	}
	if actorID := c.Query("actor_id"); actorID != "" {
		where += " AND al.actor_id = ?"
		args = append(args, actorID)
	}
	if rt := c.Query("resource_type"); rt != "" {
		where += " AND al.resource_type = ?"
		args = append(args, rt)
	}

	// Count
	var total int
	countArgs := make([]interface{}, len(args))
	copy(countArgs, args)
	countQ := convertPlaceholders(`SELECT COUNT(*) FROM audit_log al ` + where)
	err := database.DB.QueryRow(countQ, countArgs...).Scan(&total)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "count failed"})
		return
	}

	// Query — metadata column needs ::text on Postgres only
	metadataCol := "COALESCE(al.metadata::text, '{}')"
	if database.IsSQLite() {
		metadataCol = "COALESCE(al.metadata, '{}')"
	}

	query := fmt.Sprintf(`
		SELECT al.id, al.actor_id, COALESCE(u.username, '') as actor_name,
		       al.action, al.resource_type, al.resource_id,
		       %s, al.ip_address, al.created_at
		FROM audit_log al
		LEFT JOIN users u ON al.actor_id = u.id
		%s
		ORDER BY al.created_at DESC
		LIMIT ? OFFSET ?`, metadataCol, where)
	args = append(args, perPage, offset)

	query = convertPlaceholders(query)
	rows, err := database.DB.Query(query, args...)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
		return
	}
	defer rows.Close()

	entries := make([]auditEntry, 0)
	for rows.Next() {
		var e auditEntry
		var actorName sql.NullString
		if err := rows.Scan(&e.ID, &e.ActorID, &actorName, &e.Action,
			&e.ResourceType, &e.ResourceID, &e.Metadata, &e.IPAddress, &e.CreatedAt); err != nil {
			continue
		}
		if actorName.Valid {
			e.ActorName = &actorName.String
		}
		entries = append(entries, e)
	}

	c.JSON(http.StatusOK, gin.H{
		"data":     entries,
		"total":    total,
		"page":     page,
		"per_page": perPage,
	})
}

// ListAuditActions returns distinct action names for filter dropdowns.
// GET /api/v1/admin/audit/actions
func (h *AdminHandler) ListAuditActions(c *gin.Context) {
	rows, err := database.DB.Query(`
		SELECT DISTINCT action FROM audit_log ORDER BY action ASC
	`)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"actions": []string{}})
		return
	}
	defer rows.Close()

	var actions []string
	for rows.Next() {
		var a string
		if rows.Scan(&a) == nil {
			actions = append(actions, a)
		}
	}
	if actions == nil {
		actions = []string{}
	}
	c.JSON(http.StatusOK, gin.H{"actions": actions})
}