use std::collections::{BTreeMap, BTreeSet};
use std::path::Path;

use crate::ccr::{decode_ccr_compare_views, decode_content_info};
use crate::cir::decode_cir;

use super::io::{object_hash_key, parse_rfc3339, read_file, resolve_path};
use super::model::{SequenceItemRaw, SequenceMeta, SequenceSample, Side};

pub(super) fn load_sequence_meta(path: &Path, side: Side) -> Result<Vec<SequenceMeta>, String> {
    let base_dir = path.parent().unwrap_or_else(|| Path::new("."));
    let text = std::fs::read_to_string(path)
        .map_err(|e| format!("read sequence failed: {}: {e}", path.display()))?;
    let mut samples = Vec::new();
    let mut seen_seq = BTreeSet::new();
    for (line_index, line) in text.lines().enumerate() {
        let line = line.trim();
        if line.is_empty() {
            continue;
        }
        let raw: SequenceItemRaw = serde_json::from_str(line).map_err(|e| {
            format!(
                "parse sequence JSONL failed: {}:{}: {e}",
                path.display(),
                line_index + 1
            )
        })?;
        validate_raw(path, line_index, &raw, side, &mut seen_seq)?;
        let cir_path = resolve_path(base_dir, &raw.cir_path);
        let ccr_path = resolve_path(base_dir, &raw.ccr_path);
        let cir = decode_cir(&read_file(&cir_path)?).map_err(|e| {
            format!(
                "decode CIR metadata failed for sample {} ({}): {e}",
                raw.run_id,
                cir_path.display()
            )
        })?;
        let _sequence_validation_time = raw
            .validation_time
            .as_deref()
            .map(parse_rfc3339)
            .transpose()?;
        let validation_time = cir.validation_time;
        samples.push(SequenceMeta {
            cir_object_count: raw
                .cir_object_count
                .or(Some(cir.validated_object_count() as u64)),
            cir_reject_count: raw
                .cir_reject_count
                .or(Some(cir.rejected_object_count() as u64)),
            cir_trust_anchor_count: raw
                .cir_trust_anchor_count
                .or(Some(cir.trust_anchors.len() as u64)),
            raw,
            validation_time,
            ccr_path,
            cir_path,
        });
    }
    samples.sort_by(|left, right| {
        left.validation_time
            .cmp(&right.validation_time)
            .then_with(|| left.raw.seq.cmp(&right.raw.seq))
            .then_with(|| left.raw.run_id.cmp(&right.raw.run_id))
    });
    Ok(samples)
}

pub(super) fn load_sample_cir_from_meta(meta: &SequenceMeta) -> Result<SequenceSample, String> {
    load_sample_parts(meta, true, false)
}

pub(super) fn load_sample_ccr_from_meta(meta: &SequenceMeta) -> Result<SequenceSample, String> {
    load_sample_parts(meta, false, true)
}

fn load_sample_parts(
    meta: &SequenceMeta,
    include_cir: bool,
    include_ccr: bool,
) -> Result<SequenceSample, String> {
    let mut objects = BTreeMap::new();
    let mut object_hashes = BTreeSet::new();
    let mut rejects = BTreeSet::new();
    if include_cir {
        let cir = decode_cir(&read_file(&meta.cir_path)?).map_err(|e| {
            format!(
                "decode CIR failed for sample {} ({}): {e}",
                meta.raw.run_id,
                meta.cir_path.display()
            )
        })?;
        objects = cir
            .validated_objects()
            .map(|item| (item.rsync_uri.clone(), hex::encode(&item.sha256)))
            .collect::<BTreeMap<_, _>>();
        object_hashes = objects
            .iter()
            .map(|(uri, hash)| object_hash_key(uri, hash))
            .collect::<BTreeSet<_>>();
        rejects = cir
            .rejected_objects()
            .map(|item| item.object_uri.clone())
            .collect::<BTreeSet<_>>();
    }
    let mut vrps = BTreeSet::new();
    let mut vaps = BTreeSet::new();
    if include_ccr {
        let ccr = decode_content_info(&read_file(&meta.ccr_path)?).map_err(|e| {
            format!(
                "decode CCR failed for sample {} ({}): {e}",
                meta.raw.run_id,
                meta.ccr_path.display()
            )
        })?;
        let (decoded_vrps, decoded_vaps) = decode_ccr_compare_views(&ccr).map_err(|e| {
            format!(
                "decode CCR compare views failed for sample {} ({}): {e}",
                meta.raw.run_id,
                meta.ccr_path.display()
            )
        })?;
        vrps = decoded_vrps
            .into_iter()
            .map(|row| format!("{}|{}|{}", row.asn, row.ip_prefix, row.max_length))
            .collect::<BTreeSet<_>>();
        vaps = decoded_vaps
            .into_iter()
            .map(|row| format!("{}|{}", row.customer_asn, row.providers))
            .collect::<BTreeSet<_>>();
    }
    Ok(SequenceSample {
        raw: meta.raw.clone(),
        validation_time: meta.validation_time,
        objects,
        object_hashes,
        rejects,
        vrps,
        vaps,
    })
}

fn validate_raw(
    path: &Path,
    line_index: usize,
    raw: &SequenceItemRaw,
    side: Side,
    seen_seq: &mut BTreeSet<u32>,
) -> Result<(), String> {
    if raw.schema_version.unwrap_or(1) != 1 {
        return Err(format!(
            "unsupported sequence item schemaVersion in {}:{}",
            path.display(),
            line_index + 1
        ));
    }
    if !seen_seq.insert(raw.seq) {
        return Err(format!("duplicate seq {} in {}", raw.seq, path.display()));
    }
    if let Some(status) = &raw.status
        && status != "success"
    {
        return Err(format!(
            "sequence sample {} has non-success status: {status}",
            raw.run_id
        ));
    }
    if raw
        .side
        .as_deref()
        .is_some_and(|item| item != side.as_str())
    {
        return Err(format!(
            "sequence side field does not match expected side in {}:{}",
            path.display(),
            line_index + 1
        ));
    }
    Ok(())
}