using Microsoft.EntityFrameworkCore;
using PowderCoating.Core.Entities;

namespace PowderCoating.Infrastructure.Services;

public partial class SeedDataService
{
    /// <summary>
    /// Seeds <see cref="JobStatusHistory"/> transition records for every completed, delivered,
    /// or ready-for-pickup job so the Job Cycle Time report can calculate time-per-stage data.
    /// </summary>
    /// <remarks>
    /// <para>
    /// For each qualifying job the seeder builds a realistic stage sequence:
    /// PENDING &rarr; IN_PREPARATION &rarr; (SANDBLASTING if any item requires it)
    /// &rarr; (MASKING_TAPING if any item requires it) &rarr; CLEANING &rarr; IN_OVEN
    /// &rarr; COATING &rarr; CURING &rarr; QUALITY_CHECK &rarr; [terminal status].
    /// </para>
    /// <para>
    /// 85&thinsp;% of the job's total cycle time (CreatedAt &rarr; CompletedDate) is
    /// distributed across work stages using fixed per-stage weights that reflect realistic
    /// relative durations (e.g. SANDBLASTING &gt; CLEANING). The remaining 15&thinsp;%
    /// is left as residual "terminal status" time, which surfaces correctly in the report's
    /// last-entry formula <c>(job.CompletedDate &minus; last.ChangedDate)</c>.
    /// </para>
    /// <para>
    /// Idempotency: returns 0 immediately if any history records already exist for
    /// this company, matching the pattern used by all other partial seeders.
    /// </para>
    /// </remarks>
    /// <param name="company">The tenant company to seed history for.</param>
    /// <returns>Number of history records inserted, or 0 if already seeded.</returns>
    private async Task<int> SeedJobStatusHistoryAsync(Company company)
    {
        var existingCount = await _context.Set<JobStatusHistory>()
            .IgnoreQueryFilters()
            .CountAsync(h => h.CompanyId == company.Id && !h.IsDeleted);

        if (existingCount > 0) return 0;

        // Only completed-terminal jobs have a meaningful CompletedDate to calculate cycle time.
        // CANCELLED is excluded — the report cares only about successfully finished work.
        var terminalCodes = new[] { "COMPLETED", "READY_FOR_PICKUP", "DELIVERED" };

        var jobs = await _context.Set<Job>()
            .IgnoreQueryFilters()
            .Include(j => j.JobItems)
            .Include(j => j.JobStatus)
            .Where(j => j.CompanyId == company.Id && !j.IsDeleted && j.CompletedDate.HasValue)
            .ToListAsync();

        jobs = jobs.Where(j => terminalCodes.Contains(j.JobStatus.StatusCode)).ToList();
        if (jobs.Count == 0) return 0;

        var statuses = await _context.Set<JobStatusLookup>()
            .IgnoreQueryFilters()
            .Where(s => s.CompanyId == company.Id)
            .ToDictionaryAsync(s => s.StatusCode, s => s);

        var records = new List<JobStatusHistory>();

        foreach (var job in jobs)
        {
            var totalSeconds = (job.CompletedDate!.Value - job.CreatedAt).TotalSeconds;
            if (totalSeconds < 60) continue; // skip malformed dates

            var needsSand = job.JobItems.Any(i => i.RequiresSandblasting);
            var needsMask = job.JobItems.Any(i => i.RequiresMasking);

            // Build ordered stage list; the last element is the terminal "to" status only —
            // it never appears as a "from" and is not assigned a work weight.
            var stages = new List<string> { "PENDING", "IN_PREPARATION" };
            if (needsSand) stages.Add("SANDBLASTING");
            if (needsMask) stages.Add("MASKING_TAPING");
            stages.AddRange(new[] { "CLEANING", "IN_OVEN", "COATING", "CURING", "QUALITY_CHECK" });
            stages.Add(job.JobStatus.StatusCode);

            // Time weight for each "from" status — reflects typical relative hours in that stage.
            static double Weight(string code) => code switch
            {
                "PENDING"        => 2.0,  // intake / scheduling buffer
                "IN_PREPARATION" => 1.5,  // disassembly, hang, pre-inspect
                "SANDBLASTING"   => 2.0,  // media blast + blow-off
                "MASKING_TAPING" => 1.0,  // tape & plug work
                "CLEANING"       => 0.5,  // chemical wash + dry
                "IN_OVEN"        => 1.5,  // pre-heat before coating
                "COATING"        => 1.5,  // powder application
                "CURING"         => 1.0,  // oven cure cycle
                "QUALITY_CHECK"  => 0.5,  // inspection & touch-up
                _                => 0.5,
            };

            // Work stages are all entries except the terminal "to" at the end.
            int n            = stages.Count;
            var workWeights  = stages.Take(n - 1).Select(Weight).ToList();
            double totalWeight   = workWeights.Sum();
            // 85% of cycle time covers the work stages; 15% becomes terminal-status residual
            // so (job.CompletedDate − last.ChangedDate) produces a non-zero, plausible value.
            double workSeconds   = totalSeconds * 0.85;

            var currentDate = job.CreatedAt;
            for (int i = 0; i < n - 1; i++)
            {
                if (!statuses.TryGetValue(stages[i],     out var fromLookup)) continue;
                if (!statuses.TryGetValue(stages[i + 1], out var toLookup))   continue;

                currentDate = currentDate.AddSeconds(workSeconds * workWeights[i] / totalWeight);

                records.Add(new JobStatusHistory
                {
                    JobId        = job.Id,
                    FromStatusId = fromLookup.Id,
                    ToStatusId   = toLookup.Id,
                    ChangedDate  = currentDate,
                    CompanyId    = company.Id,
                    CreatedAt    = currentDate,
                });
            }
        }

        if (records.Count == 0) return 0;

        await _context.Set<JobStatusHistory>().AddRangeAsync(records);
        await _context.SaveChangesAsync();
        return records.Count;
    }
}