using System;
using System.Collections.Generic;
using System.Text;

namespace Colosseum.Combat.Simulation
{
    /// <summary>
    /// 결과 미리보기/추출 포맷입니다.
    /// </summary>
    public enum SimulationReportFormat
    {
        DetailText,
        Markdown,
        Csv,
    }

    /// <summary>
    /// 허수아비 계산 시뮬레이터 결과를 외부 공유용 문자열로 변환합니다.
    /// </summary>
    public static class SimulationReportUtility
    {
        /// <summary>
        /// 선택한 포맷으로 결과 문자열을 생성합니다.
        /// </summary>
        public static string BuildReport(SimulationResult result, SimulationReportFormat format)
        {
            if (result == null)
                return string.Empty;

            return format switch
            {
                SimulationReportFormat.Markdown => BuildMarkdown(result),
                SimulationReportFormat.Csv => BuildCsv(result),
                _ => result.DetailText,
            };
        }

        /// <summary>
        /// 마크다운 리포트를 생성합니다.
        /// </summary>
        public static string BuildMarkdown(SimulationResult result)
        {
            if (result == null)
                return string.Empty;

            StringBuilder builder = new StringBuilder();
            builder.Append("# 허수아비 계산 시뮬레이션 결과");
            builder.AppendLine();
            builder.AppendLine();
            builder.Append("- Build: ");
            builder.Append(result.BuildLabel);
            builder.AppendLine();
            builder.Append("- Rule: ");
            builder.Append(result.RuleName);
            builder.AppendLine();
            builder.Append("- Rotation: ");
            builder.Append(result.RotationName);
            builder.AppendLine();
            builder.AppendLine();

            builder.AppendLine("| 항목 | 값 |");
            builder.AppendLine("| --- | --- |");
            builder.Append("| Duration | ");
            builder.Append(result.DurationSeconds.ToString("0.##"));
            builder.AppendLine("s |");
            builder.Append("| Total Damage | ");
            builder.Append(result.TotalDamage.ToString("0.##"));
            builder.AppendLine(" |");
            builder.Append("| DPS | ");
            builder.Append(result.AverageDps.ToString("0.##"));
            builder.AppendLine(" |");
            builder.Append("| Total Mana | ");
            builder.Append(result.TotalManaUsed.ToString("0.##"));
            builder.AppendLine(" |");
            builder.Append("| Mana / Sec | ");
            builder.Append(result.AverageManaPerSecond.ToString("0.##"));
            builder.AppendLine(" |");
            builder.Append("| First Cycle End | ");
            builder.Append(result.FirstCycleEndTime >= 0f ? result.FirstCycleEndTime.ToString("0.##") + "s" : "미완료");
            builder.AppendLine(" |");

            if (result.SkillBreakdowns.Count > 0)
            {
                builder.AppendLine();
                builder.AppendLine("## 스킬 기여도");
                builder.AppendLine();
                builder.AppendLine("| 스킬 | 사용 횟수 | 누적 피해 |");
                builder.AppendLine("| --- | ---: | ---: |");

                for (int i = 0; i < result.SkillBreakdowns.Count; i++)
                {
                    SimulationSkillBreakdown entry = result.SkillBreakdowns[i];
                    builder.Append("| ");
                    builder.Append(entry.SkillName);
                    builder.Append(" | ");
                    builder.Append(entry.CastCount);
                    builder.Append(" | ");
                    builder.Append(entry.TotalDamage.ToString("0.##"));
                    builder.AppendLine(" |");
                }
            }

            if (result.Warnings.Count > 0)
            {
                builder.AppendLine();
                builder.AppendLine("## 경고");
                builder.AppendLine();
                for (int i = 0; i < result.Warnings.Count; i++)
                {
                    builder.Append("- ");
                    builder.Append(result.Warnings[i]);
                    builder.AppendLine();
                }
            }

            return builder.ToString().TrimEnd();
        }

        /// <summary>
        /// CSV 리포트를 생성합니다.
        /// </summary>
        public static string BuildCsv(SimulationResult result)
        {
            if (result == null)
                return string.Empty;

            StringBuilder builder = new StringBuilder();
            builder.AppendLine("BuildLabel,RuleName,RotationName,DurationSeconds,TotalDamage,AverageDps,TotalManaUsed,AverageManaPerSecond,FirstCycleEndTime,SkillName,CastCount,SkillDamage,Warnings");

            string warnings = string.Join(" / ", result.Warnings);
            IReadOnlyList<SimulationSkillBreakdown> breakdowns = result.SkillBreakdowns;

            if (breakdowns.Count == 0)
            {
                AppendCsvRow(builder, result, null, warnings);
                return builder.ToString().TrimEnd();
            }

            for (int i = 0; i < breakdowns.Count; i++)
            {
                AppendCsvRow(builder, result, breakdowns[i], warnings);
            }

            return builder.ToString().TrimEnd();
        }

        /// <summary>
        /// 저장에 적합한 기본 파일 이름을 생성합니다.
        /// </summary>
        public static string BuildDefaultFileName(SimulationResult result, SimulationReportFormat format)
        {
            string baseName = result != null
                ? $"{result.BuildLabel}_{result.RuleName}_{result.RotationName}"
                : "BuildSimulation";

            string extension = format == SimulationReportFormat.Csv ? "csv" : "md";
            return $"{SanitizeFileName(baseName)}.{extension}";
        }

        private static void AppendCsvRow(
            StringBuilder builder,
            SimulationResult result,
            SimulationSkillBreakdown breakdown,
            string warnings)
        {
            builder.Append(EscapeCsv(result.BuildLabel));
            builder.Append(',');
            builder.Append(EscapeCsv(result.RuleName));
            builder.Append(',');
            builder.Append(EscapeCsv(result.RotationName));
            builder.Append(',');
            builder.Append(result.DurationSeconds.ToString("0.##"));
            builder.Append(',');
            builder.Append(result.TotalDamage.ToString("0.##"));
            builder.Append(',');
            builder.Append(result.AverageDps.ToString("0.##"));
            builder.Append(',');
            builder.Append(result.TotalManaUsed.ToString("0.##"));
            builder.Append(',');
            builder.Append(result.AverageManaPerSecond.ToString("0.##"));
            builder.Append(',');
            builder.Append(result.FirstCycleEndTime >= 0f ? result.FirstCycleEndTime.ToString("0.##") : string.Empty);
            builder.Append(',');
            builder.Append(EscapeCsv(breakdown != null ? breakdown.SkillName : string.Empty));
            builder.Append(',');
            builder.Append(breakdown != null ? breakdown.CastCount.ToString() : string.Empty);
            builder.Append(',');
            builder.Append(breakdown != null ? breakdown.TotalDamage.ToString("0.##") : string.Empty);
            builder.Append(',');
            builder.Append(EscapeCsv(warnings));
            builder.AppendLine();
        }

        private static string EscapeCsv(string value)
        {
            if (string.IsNullOrEmpty(value))
                return string.Empty;

            bool needsQuotes = value.Contains(",") || value.Contains("\"") || value.Contains("\n") || value.Contains("\r");
            if (!needsQuotes)
                return value;

            return $"\"{value.Replace("\"", "\"\"")}\"";
        }

        private static string SanitizeFileName(string value)
        {
            if (string.IsNullOrWhiteSpace(value))
                return "BuildSimulation";

            string sanitized = value;
            char[] invalidChars = System.IO.Path.GetInvalidFileNameChars();
            for (int i = 0; i < invalidChars.Length; i++)
            {
                sanitized = sanitized.Replace(invalidChars[i], '_');
            }

            return sanitized.Replace(' ', '_');
        }
    }
}